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