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