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