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