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