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