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