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)(11,20)(12,17)(13,23)(14,18)(15,19)(16,22)(21,24)(25,26,31,35)(27,36,39,32)(28,33,40,30)(29,37,38,34)(1,3,5,8)(2,6,4,7)(9,11)(10,16)(12,14)(13,18)(15,22)(17,24)(19,20)(21,23)(25,27)(26,32)(28,37)(29,33)(30,38)(31,39)(34,40)(35,36)(9,12,15,23)(10,13,19,17)(11,21,22,14)(16,24,20,18)(25,28,31,40)(26,30,35,33)(27,37,39,34)(29,32,38,36)(1,2,5,4)(3,6,8,7)(9,12)(10,17)(11,14)(13,19)(15,23)(16,24)(18,20)(21,22)(25,28)(26,33)(27,37)(29,32)(30,35)(31,40)(34,39)(36,38)(9,13,15,17)(10,12,19,23)(11,18,22,24)(14,20,21,16)(25,29,31,38)(26,34,35,37)(27,33,39,30)(28,32,40,36)(1,4,5,2)(3,7,8,6)(9,14)(10,18)(11,12)(13,16)(15,21)(17,20)(19,24)(22,23)(25,30,31,33)(26,28,35,40)(27,38,39,29)(32,37,36,34)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.