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