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