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