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