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