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