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