One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(3,7)(9,10,13,18)(11,20,23,35)(12,17,15,26)(14,29,28,40)(16,30,32,24)(19,27,33,21)(22,34,25,39)(31,37,36,38)(1,2)(3,6)(4,5)(7,8)(9,10)(11,16)(12,26)(13,18)(14,19)(15,17)(20,24)(21,29)(22,36)(23,32)(25,31)(27,40)(28,33)(30,35)(34,37)(38,39) involution — undirected(9,11,21,37,15,25,28,30,13,23,27,38,12,22,14,24)(10,16,29,34,17,31,33,35,18,32,40,39,26,36,19,20)(2,5)(6,8)(9,12,13,15)(10,17,18,26)(11,22,23,25)(14,27,28,21)(16,31,32,36)(19,29,33,40)(20,34,35,39)(24,38,30,37)(1,3,4,7)(2,6,5,8)(10,18)(16,32)(17,26)(19,33)(20,35)(29,40)(31,36)(34,39)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.