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