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