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