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