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