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