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