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