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