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