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