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