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