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