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)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26,30,31)(27,32,35,39)(28,36,37,33)(29,34,38,40)(9,11,13,19)(10,14,16,17)(12,18,20,24)(15,21,22,23)(25,27)(26,32)(28,34)(29,33)(30,35)(31,39)(36,38)(37,40)(2,5)(6,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,28)(26,33)(27,29)(30,37)(31,36)(32,40)(34,39)(35,38)(10,16)(14,17)(15,22)(21,23)(27,35)(28,37)(32,39)(33,36) involution — undirected(1,3,4,7)(2,6,5,8)(11,19)(14,17)(18,24)(21,23)(25,29)(26,34)(27,28)(30,38)(31,40)(32,36)(33,39)(35,37)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.