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