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