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