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