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