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