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