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