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