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