One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,7)(6,8)(9,10,13,19,15,20,14,16)(11,21,24,32,25,30,23,17)(12,18,26,33,28,34,27,29)(22,35,37,40,38,39,36,31)(1,3)(2,4)(5,8)(6,7)(10,16)(12,26)(13,14)(17,30)(19,20)(21,32)(22,36)(23,24)(27,28)(29,33)(31,40)(37,38) involution — undirected(1,4,6,5)(2,7,8,3)(9,11)(10,17,20,32)(12,22)(13,23)(14,24)(15,25)(16,21,19,30)(18,31,34,40)(26,36)(27,37)(28,38)(29,35,33,39)(1,5,6,4)(2,7,8,3)(9,12,13,26,15,28,14,27)(10,18,19,33,20,34,16,29)(11,22,23,36,25,38,24,37)(17,31,30,39,32,40,21,35)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.