You can find at least one such (annual) report online. Nearly 30 pages, a lot of large colour pages (nice), and a surplus of relatively unsurprising and disappointingly presented graphs (not so nice) all about accident numbers (or rather, how many forms have been filled in). Too large for what they have to say - hence the high page count.
However, at the end of the multiple graphs, the really key points are in the narrative where the figures (repeatedly pie & bar charted) are acknowledged to say little, and the key priorities are those high risk areas where any accident could be a killer, and this cannot be gleaned from the data so boldly presented.
So - what IS useful to present to board level? I like one page, two at most, for quarterly summaries, but could go to 10 for annual report, including objectives and progress etc.
Attractive & clean appearance, simple, meaningful data, and purposeful recommendations. What the board want is overview, big picture, how are we doing? Useful data means trends and 'ratings' helping to tell the story of direction of travel. Imagine the sort of questions which could be asked as a result of the presentation, and try to get the data to provide the answers. Minimal focus on accidents as numbers, more interpretation - what is this telling us? "We are weak in the areas of . . . Performance on . . . has improved".etc. Numbers of forms filled in is not the same as performance rating. Without rates, (ie employee numbers, hours / days worked) accident form counting is pointless anyway. Riddor - these are (usually) so random and low there is no point in minutely comparing. Just give a number - 'this many' as a factual.
Now on a personal rant, prompted by looking at yet another standard safety report. If using Excel to produce graphs or charts, please learn to change the default settings! Even in colour, dark print on dark colours is unclear. A good test is to print in monochrome as well, to check that your (paler, distinct) colours work. Remove clutter (backgrounds, lines, boxes).
Pie charts rarely work well especially if more than 5 items. If all the slices are pretty much the same in size, what's the story? Find a better way.
Bar charts - try putting the items in an order which makes sense: Often biggest first. Don't just use whatever order the system defaults to (alphabetical) unless this makes reader-sense. Trend line graphs are good (3 years max).
Unfortunately nearly all such reports default to the 'numbers' of accidents, presented in numerous creative but unhelpful ways. Then there is a tendency to home in on 'pro-activities' such as numbers of audits, training events etc. very rarely answering the 'so what?' question.
Dare to be different. Then share your success with us all!