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